The invention relates to an editing apparatus, such as, for example, in an impact line printer for automatically editing type arrangement data corresponding to the kind of loaded type carrier utilized.
In a conventional line printer, a group of type data codes which are produced by a data source such as CPU are successively compared to type arrangement data determined in accordance with the instantaneous position of a type carrier. When coincidence is detected between the type data code and the instantaneous type carrier position, the symbol in question is printed out. Typical line printers have type carriers such as print bands, print drums, print trains, print chains, etc. By way of example, the following discussion will be made with reference to a type carrier of the print band type.
Since the type arrangement data is determined in accordance with the kind of print band to be used, it is necessary to replace the type arrangement data when the print band is replaced. To this end, plural kinds of type arrangement data corresponding to plural kinds of print bands, respectively, are written into plural ROMs (read only memories). Thus, a particular ROM corresponding to a particular loaded print band may be selectively used to thereby obtain the type arrangement data corresponding to the print band in question. However, since the ROMs correspond to the print bands on a one-to-one basis, if there is a second type of arrangement data which is different from the first type arrangement data stored in the ROM, it is necessary to load another ROM into the line printer which corresponds to this second type arrangement data even if the difference between the first and second type of arrangement datum is relatively minor.
Therefore, as the number of different kinds of print bands having discrete type arrangement data increases, the number of ROMs to be loaded into the line printer correspondingly increases. However, it has been found that there is a limit as to the number of ROMs which can be loaded into the line printer. These limitations are due to both cost and loading space constraints. Specifically, four ROMs have been found to be an optimal number. Thus, in the above-described method in which data in ROMs loaded into a line printer are used as type arrangement data corresponding to the print bands of the line printer, it has been found that the number of different print bands which can be used is limited by the four-ROM optimal capacity of the line printer.